CARACAS, Venezuela — The Organization of American States said Tuesday that it had begun taking steps against Venezuela to defend democracy in the region, a rare rebuke once reserved for countries undergoing crises like coups.

The move by the O.A.S., a United Nations-like group that represents every country in the hemisphere except for Cuba, now starts a process that could eventually lead to Venezuela being suspended from the body.

Venezuela’s Legislature, controlled by rivals of the country’s governing leftists for the first time in more than a decade, has been stymied by government-backed courts. And protests to recall the president in a referendum have been quashed with tear gas and security forces.

“There has been an erosion of democracy on so many levels this year,” said Shannon K. O’Neil, a senior fellow at the Council on Foreign Relations.

Perhaps Venezuela’s most outspoken critic this year has been the O.A.S., in a confrontation that has grown increasingly personal and acrimonious.

This month, Mr. Maduro went on television to accuse Mr. Almagro, who is Uruguay’s former foreign minister, of having shadowy ties to the United States.

“Almagro is a longtime traitor,” Mr. Maduro said. “A C.I.A. agent.”

Mr. Almagro responded with an angry open letter the following day, saying that he was not a member of the C.I.A. and said Mr. Maduro had betrayed his people.

“To deny the people that vote,” he said, referring to the referendum, “to deny them the possibility of deciding, would make you just any other petty dictator, like so many this hemisphere has had.”

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President Nicolás Maduro remained defiant after the Organization of American States formally called for outside intervention in the embattled country.CreditCreditCarlos Garcia Rawlins/Reuters

In the days since, the country’s leftists have responded with continued public attacks and a barrage of memes on Twitter showing unflattering photos of Mr. Almagro’s face against the American flag.

The bitter exchanges underscored what analysts said was increasing isolation of Venezuela from its neighbors. The country once had a reliable stable of allies among leftists throughout the region.

But the impeachment trial in Brazil, in which President Dilma Rousseff has been suspended, and the defeat last year of leftist Peronists in Argentina have left Venezuela with new, more skeptical leaders in neighboring countries.

“The golden age of socialism in the 21st century is over in South America,” said María Teresa Romero, a Venezuelan political scientist, referring to troubles leftists have faced throughout the region.

The events also showed the trouble Venezuela has faced in maintaining its influence at a time when oil prices have remained low.

In the past, Venezuela managed a reliable voting block in the O.A.S. by doling out largess through groups like Petrocaribe, an organization where Venezuela provides cheap oil to Caribbean nations. It also bankrolled regional groups like Unasur, a more pliant body that replicated jobs handled by the O.A.S., like election observing. But the current economic crisis has put the pinch on both.

On Tuesday, leftists quickly blasted the O.A.S. once more. Pedro Carreño, a legislator from Mr. Maduro’s socialist party said Venezuela still enjoyed support in the region and Mr. Almagro didn’t have the votes to suspend Venezuela. He said the O.A.S. was now “at the service of dark interests that run contrary to democracy and are conspiring again against our democratic government.”

By invoking its Democratic Charter the organization effectively began a process of debate that could eventually lead to Venezuela’s suspension. But analysts say the more likely avenue initially will be a series of discussions to break the political stalemate between Mr. Maduro and his opponents who control the National Assembly.

Some steps to that end have already taken place. Over the weekend, the two sides said they had begun passing messages through mediators during a conference in the Dominican Republic.

The main issue will be whether the country holds the referendum on Mr. Maduro. Mr. Maduro, the handpicked successor of President Hugo Chávez, has dismal approval ratings amid the lack of food and electricity in the country. He has repeatedly said that the recall is an attempt to overthrow him and should be blocked.

The O.A.S. evoked its democratic charter after a 2009 military coup that overthrew President Manuel Zelaya in Honduras. The country was eventually suspended from the group and reinstated after it held an election and Mr. Zelaya returned to Honduras.

Dr. O’Neil said Tuesday’s events had implications not just for Venezuela, but also for the O.A.S., which she says has taken the role of a democratic watchdog under Mr. Almagro.

“Almagro from the beginning has been adamant about this: The one thing the O.A.S. does that no other body does in his mind is defend democracy,” she said. “That’s why he has taken such a hard line.”